The common bile duct is about eight (8) to ten (10) millimeters in diameter and may dilate if obstructed by biliary stones or other foreign matter. The common bile duct tapers to a diameter of one (1) millimeter as it enters the wall of the duodenum. In this area, smooth muscle fibers surround both the common bile duct and the pancreatic duct which enter the duodenum from the side. These fibers are collectively called the sphincter of Oddi and are responsible for the tapering of the common bile duct as it transverses the duodenal wall. If the common bile duct joins to the pancreatic duct within the duodenal wall, the resulting structure is called the ampulla of Vater. This small protrusion can frequently be seen from the inside of the duodenum, but on some patients, it is too small for visualization.
If the sphincter of Oddi impedes the passage of stones in the common bile duct, it is cut in an operation called a sphincterotomy. A sphincterotomy often involves opening the duodenum, locating the small papilla called the ampulla of Vater, and incising the fibers at a particular radial position to avoid injury to the pancreatic duct. It is a difficult procedure, and the possibility of complications from either pancreatitis from an injury to the pancreatic duct or a fistula from the duodenum or common duct are very serious. An alternate procedure that can be performed lieu of a sphincterotomy is to anastomose the common duct to the duodenum or other small bowel. This is also a difficult procedure from which there is also a possibility of a fistula if the anastomosis leaks.
A sphincterotomy may alternatively be performed endoscopically through a side-viewing gastroduodenoscope. This type of sphincterotomy was first performed in 1974 and has become the method of choice. When performed endoscopically, general anesthesia is not needed and the duodenum is not opened. This method has been recommended for use after laparoscopic cholangiograms reveal the presence of common duct stones. The patient is allowed several days to recover from a laparoscopic cholecystectomy before being endoscoped via a side-viewing gastroduodenoscope. After retrograde cholangiopancreatography and X-ray pictures of the biliary and pancreatic ducts are completed, the sphincterotomy is performed. Large common duct stones are retrieved using stone baskets or other instruments. Small stones are left to be washed out of the common duct into the duodenum after the sphincterotomy is complete. In most instances, a general surgeon performs the laparoscopic cholecystectomy and a gastroenterologist treats the common duct stones. The patient undergoes two major procedures and two sets of multiple X-rays.
Representative of the type of surgical equipment used for endoscopically completing a sphincterotomy is the Olympus Endoscopy System available from Olympus Corporation in Lake Success, N.Y. To perform the incision in a sphincterotomy, a papillotomy knife (such as Olympus models KD-4Q, KD-5Q, and KD-6Q) is used in conjuction with a fiberscope (such as the Olympus JF-10 ERCF Duodenofiberscope). Through the limited vision provided through the laparoscopic ports, the papillotomy knife catheter is positioned and the cutting edge is moved by controls made available to the surgeon to incise the fibers. Special care must be taken with such a procedure to properly position the cutting edge and to maintain that position until the incision is complete.
Several catheters are available for the removal or destruction of calculi or stones within the body. U.S. Pat. No. 4,911,163, discloses a device used for the removal of calculi from the ureter; U.S. Pat. No. 4,627,837, discloses a device used for the removal of stones from the common duct; and U.S. Pat. No. 4,561,439, discloses a device used for the removal of gall stones. Each of these patents disclose catheters in which balloons are at or near the distal end of the device and are used to perform their respective functions. Generally, the balloons are used to hold the stones while they are dragged out of the appropriate duct. U.S. Pat. No. 4,627,837 uses one balloon at the distal end of the catheter to anchor the catheter at the sphincter of Oddi and a second balloon near the distal end of the catheter to catch and remove the stones located in the common bile duct near the sphincter of Oddi. U.S. Pat. No. 3,108,593 discloses a catheter in which cages or bobbins are positioned from the distal end of the catheter and which dislodges and entraps bile duct stones, but which requires that incisions be made in the duodenum and the common bile duct.
The device disclosed in U.S. Pat. No. 4,811,735 is used to destroy stones through the use of rotating blades at the distal end of the catheter. U.S. Pat. Nos. 4,696,668 and 4,781,677 disclose a catheter that can be utilized to destroy stones by injecting a dissolving agent into the gall bladder after positioning the two inflated balloons near the distal end of the catheter within the common bile duct. Similar techniques are employed in the device disclosed in U.S. Pat. No. 4,734,094 wherein a contrast fluid can be injected in between the ballons at the end of the catheter for X-ray cholangiography.
Several other ballooned catheters exist for a variety of purposes. The catheter disclosed in U.S. Pat. No. 4,271,839 is used for the dilation of occluded blood vessels. Commercially available products include the Flexiflo(R) Gastrostomy Tube available from Ross Laboratories, Columbus, Ohio.
U.S. Pat. No. 4,705,041 discloses a catheter and a method used to dilate the sphincter of Oddi during open surgery. The catheter does not include a balloon, but does include an expandable tip used to position the distal end of the catheter in preparation for the placement of tube-like dilators over the catheter.
A multi-functional catheter used to complete a commissurotomy is disclosed in U.S. Pat. No. 4,484,579. This device comprises balloons at the distal end of the catheter as well as cutting edges located between the balloons such that, once the balloons are positioned, the cutting edges are able to separate fused heart valves.
To endoscopically perform a sphincterotomy in the most efficient manner requires a catheter that can be inserted into the common bile duct, threaded into the duodenum through the sphincter of Oddi, radially positioned within the ampulla, and then make the necessary incision. None of the above references can be used in this manner.